The primary outcome of this study is the assessment of feasibility. A sample of 100 participants allows for the estimation of the standard deviation of GWG, a continuous variable, and will give reliable data on the critical recruitment parameters for planning of a larger intervention trial
[38]. While the study will not be adequately powered to detect GWG differences between groups, the sample is comparable in size to that of previous GWG studies [39,40] and will provide 80% power with an alpha of 5% to detect a 3-kg difference in GWG (secondary outcome) between the 2 groups, assuming a standard deviation of GWG of 5 kg and allowing for a 10% drop out.